Accurate measurement of the aeroballistic flight characteristics of spinning bodies, with on-board sensors, significantly contributes to the research and development of experimental projectiles, and to the diagnosis of existing munitions systems.
Various systems exist for obtaining projectile data while the projectile is still traveling within the bore of a gun barrel. The in-bore techniques have not been able to provide good quality measurements for many reasons. These in-bore techniques have included: 1) Hardwiring of sensors on-board the projectile directly to recording equipment located outside of the gun tube. This technique suffered from wire breakage and loss of data. 2) Radio frequency transmission of the in-bore data out of the gun. This technique has loss of data due to the ionized gasses obscuring the RF signal. 3) Laser beam transmission of the in-bore data out of the gun tube. The major difficulty with this technique was the critical alignment requirements of the transmitter and its receiving station. In addition, blow-by gasses leaking around the projectile as it traveled up the gun tube usually obscured and attenuated the laser light beam and resulted in further loss of data. 4) On-board recorders that store the in-bore measurements. Recovery of the projectile is extremely difficult. Many artillery projectiles are fired in excess of 20 km and penetrate deep into the earth. Many proving grounds fire into areas off limits or into water making recovery impossible. 5) An on-board telemetry system that stores the in-bore measurement data and then transmits it after a delay. This type of system has only measured the in-bore data and the volume taken up by the system has required major modification to the projectile.
For a complete analysis, data during the projectile""s flight outside the gun barrel is also required. Ground-based instrumentation systems can provide some of these measurements, but are generally used for only limited portions of a projectile flight for reasons of both expense and practicability in application. In another system, such as shown in U.S. Pat. No. 5,909,275, light sensors positioned around a fuze-like body of a projectile, to sense the sun, are used to provide parameters pertaining to the solar attitude and solar roll angle.
There is a need, however, for a system which is capable of obtaining aeroballistic data, starting from a projectile""s initial in-bore launch and throughout its entire flight with no loss of data.
The diagnostic system of the present invention meets the objective of obtaining aeroballistic data starting from a projectile""s initial in-bore launch from a gun and throughout its entire flight, with no loss of data.
The diagnostic system includes a container which can attach to the projectile, and has a fuze shaped body. The interior holds a plurality of sensor arrays, one of which obtains projectile data during in-bore travel of the projectile. Other ones of the sensor arrays obtain projectile data during in-flight travel of the projectile. Also positioned within the container is a recording means which, when activated, stores the in-bore data, at a first rate, and reads the data out, at a slower rate, while the projectile is in-flight. The in-bore data and the in-flight data are encoded and provided to a utilization means, such as a transmitter and associated antenna, also within the container, for transmission of both in-bore and in-flight data to a ground station, for processing of the data. In another embodiment the utilization means is comprised of a microprocessor and guidance control unit for governing flight direction of the projectile.